"Loop" usually refers to a technical analysis method in stock or futures market. It means that in a period of time, the price trend shows a trend of falling first and then rising, and a "U" curve is formed on the chart. When the price trend forms this U-shaped curve, it is called "turning back line". The "return line" is usually regarded as a buying signal, because it shows that the market has bottomed out and is rebounding. Investors can buy related stocks or futures contracts according to the emergence of the "tropic of cancer" in order to obtain the benefits of rising prices.
It should be noted that "loop" is only a technical analysis method, and it does not guarantee that investors will definitely get benefits. When making investment decisions, other factors need to be considered, such as market trends and company fundamentals.